Evaluation of TlOH Effect for Pd⁰-Mediated Cross-Coupling of Methyl Iodide and Excess Boronic Acid Ester toward Fabrication of [¹¹C]CH₃-Incorporated PET Tracer

The use of thallium(I) hydroxide (TlOH) as a base is known to extremely accelerate the Suzuki-Miyaura cross-coupling reaction using organoboronic acid or organoboronic acid ester as a substrate. Here, we investigated the effects of TlOH by comparing with other conventional bases such as KOH, K2CO3, and CsF for Pd0-mediated rapid cross-coupling reactions between CH3I and organoborane reagents, such as phenyl-, (Z)-4-benzyloxy-2-butenyl-, and benzylboronic acid pinacol esters under the conditions CH3I/borane/Pd0/base (1:40:1:3) in THF/H2O or DMF/H2O for 5 min with an aim to fabricate a PET tracer efficiently. Consequently, however, the use of TlOH was much less efficient than the other bases for the acceleration of cross-coupling reactions. Thus, it was reconfirmed that the milder and non-toxic conditions using K2CO3 or CsF so far developed by our group were most appropriate for the rapid C-methylations.

基于SNP芯片分析的蓝塘猪遗传群体结构

为了保护和利用蓝塘猪种质资源,采用Illumina CAUPorince 50K SNP芯片对139头蓝塘猪进行遗传群体结构分析。结果显示,SNP芯片基因型分型的平均检出率高达98.24%,表明该芯片适合应用于中国地方猪。蓝塘猪的平均遗传距离值为0.3326±0.0339,主成分分析和G矩阵结果表明部分种猪之间亲缘关系较近。139头蓝塘猪种猪可以分成5个家系,分别为家系A、B、C、D和E,其中家系A、B、C和D均有种公猪。蓝塘猪的Y染色体共有两种单倍型,其中家系A和B属于单倍型A,家系C和D属于单倍型B。在蓝塘猪中共检测到1 680个ROH片段,10~20 Mb长度的ROH数量最多、占44.52%,平均每个蓝塘猪的ROH数量为12.09(±5.90)个,平均总长度为246.90(±170.93)Mb。通过SNP芯片,从遗传水平反映了一个蓝塘猪种群的群体结构,为地方猪种的保种、开发与利用提供了有力工具。